1. Field of the Invention
The present invention relates to a percussion device for an automatic weapon with a barrel of the type powered by an internal energy source (such as of the gas operated type), or with an external energy source.
2. Description of the Prior Art
In the current state of the art, there are three types of percussion devices:
spring-driven mechanisms such as those used in Gatling type weapons, consisting of a firing pin sliding in the breech block and driven by a spring tht is compressed as the breech moves forward in the weapon, held in position by a stop and then released by retracting the stop after locking the breech on the weapon barrel. PA1 it includes a counterpin integral with the carrier piece that can slide with respect to the firing pin and which cooperates with the said linking means; PA1 the course of travel of the counterpin with respect to the firing pin is roughly equal to the recoil-absorbing course of travel; PA1 the first linking means consists of at least one lever pivoting on the firing pin about an axis perpendicular to the barrel axis, having a surface bearing on a corresponding inner surface on the movable bolt head, cooperating with a shoulder on the counterpin and retracting into a recess in the movable bolt head to release the link; PA1 the second linking means consists of at least one lever pivoting on the firing pin about an axis perpendicular to the gun barrel axis, having a surface bearing on a corresponding outer surface on the counterpin, cooperating with a notch in the inner surface of the movable bolt head and retracting into a recess in the counterpin to release the link; PA1 the step in the counterpin has a recess allowing for the penetration of the lever into the counterpin shoulder; PA1 the recess in the movable bolt head is used as a notch for locking the firing pin with the movable bolt head; PA1 the recess in the counterpin is used as a shoulder for locking the firing pin with the counterpin; PA1 the lever is used for the first and second means of linking .
The main disadvantage of these mechanisms is that the firing pin speed, and thus the percussion energy, depend on the stiffness of the spring, which may vary during the lifetime of the weapon. Also, since the firing pin is not secured to the breech after the percussion and during the recoil absorption phase, the firing pin may be thrown violently to the rear due to the large pressures developed on the percussion cap during the combustion of the propulsive charge.
Inertial mechanisms consist of a firing pin of set mass sliding in the breech block, driven by the forces of inertia. When the breech impacts with and locks on the weapon barrel, the firing pin is projected toward the ammunition and initiates it.
This type of device presents disadvantages similar to those of the previously described mechanism, since the friction of the firing pin in the breech block (due to surface condition, insufficient lubrication, and dirtying) may change the percussion energy. The firing pin is not integral with the breech block during the locking and percussion phases of operation.